Desert Woodrat

Desert woodrats are relatively small for pack rats. Males in thisspecies are larger than females. The coloring of these animals varies between individuals, and can be anything from pale gray to cinnamon to near-black. The underparts and feet are always white, while the pale fur on the throat region is gray at its base. The tail is distinctly bicolored, and has more hair, and fewer visible scales, than the tails of brown rats. Desert woodrats have a narrow snout, long whiskers, and relatively long ears that are almost the length of the hind feet.

Distribution

Desert woodrats are found in North America. They range from southeastern Oregon and southwestern Idaho, south through Nevada and western Utah to California in the US, and Baja California and extreme northwestern Sonora in Mexico. Twenty three subspecies are recognised and many of them restricted to small islands in the Gulf of California. Desert woodrats are generally found in sagebrush scrub areas, in chaparral, and in deserts and rocky slopes with scattered cactus, yucca, pine/juniper, and other low vegetation. They are most abundant in rocky areas with numerous crevices or rock piles in which they can seek shelter from predators.

Geography

Biome

Climate zones

Habits and Lifestyle

Desert woodrats are primarily nocturnal and are aggressively solitary. They may defend water sources against other species, and perhaps prevent other species from obtaining water during droughts. Woodrats construct houses for nesting, food caching, and predator escape. Their houses are located against rock crevices, at the base of cactus plants, or in the lower branches of trees. They can have up to 6 entrances and 8 internal chambers, including both nests and food caches. Nests are constructed of dried vegetation, usually fibrous grass parts or shredded stems. Desert woodrats sometimes appropriate the burrows of ground squirrels or kangaroo rats. They will strengthen the entrance with sticks and joints collected from cactus. This provides a formidable defense against predators. Males mark their territory by rubbing themselves on the ground. Females, however, scent mark by first digging, and then rubbing their flanks, legs or cheeks on the excavated soil. They are active year-round.

Diet and Nutrition

Desert woodrats are herbivores and granivores. They feed on beans and leaves of mesquite, on juniper, and on parts of available cacti. They also eat creosote bushes, thistles, Ephedra, Mustard plants, sagebrush, and buckwheat. Desert woodrats will also eat other green vegetation, seeds, fruits, acorns, and pine nuts.

Mating Habits

Little information is available about the mating system in Desert woodrats. These animals breed in the spring and summer. Females give birth to litters of up to 5 young after a gestation period of 30-36 days. The young weigh about 10 g (0.35 oz) at birth, and are blind, with only the tips of their hairs visible. Their eyes open after about ten days. The young are weaned at around 4 weeks of age and ready to breed when they are 2-3 months of age.

Population

Population threats

There are no major threats to Desert woodrats. However, some populations in the northwestern part of Mexico may suffer from habitat change and from introduced species, such as cats.

Population number

According to IUCN Red List, Desert woodrats are common and widespread throughout their known range, but no overall population estimate is available. This species’ numbers remain stable today and it is classified as Least Concern (LC) on the IUCN Red List.